1. Field of the Invention
This invention is in the field of diodes which are sensitive to magnetic fields, the diode having a body of silicon, and p-injecting and n-injecting contact electrodes, the n-injecting electrode being lithium, and the p-injecting electrode preferably being aluminum.
2. Description of the Prior Art
A magnetic sensitive silicon diode has been described in the article by Arai et al, entitled "Silicon Magnetodiode" published in the Proceedings of the Second Conference on Solid State Devices, (Tokyo 1970). A similar diode composed of germanium has been described in "Radio Mentor" Vol. 34 (1968) No. 4, pages 200 to 202. Diodes of this type have a surface of particularly high recombination speed which is achieved by introducing impurities into the surface.
The magnetic field sensitivity of such diodes is based upon the so-called Lorentz force: moving electrical charges are deflected from their original path by a magnetic field whose direction is perpendicular to the direction of motion of the charges, the deflection taking place in a direction which is perpendicular to the original direction of motion and perpendicular to the direction of the field.
If a diode of this type is biased in the forward direction, then the n-charge carriers move in the electric field from the n-injecting electrode to the p-injecting electrode, while the p-charge carriers move in the reverse direction. A magnetic field can be set up which, because of the Lorentz force, causes the charge carrier pairs to be deflected either in the direction toward the surface having a high rate of recombination, or in the direction toward a surface having a lower recombination rate. In the first instance, the magnetic field reduces the number of free charge carrier pairs while in the second case, the number is increased. The latter case corresponds to a negative magneto resistance, i.e., the magnetic field reduces the resistance in the forward direction while the former case corresponds with positive magneto resistance, i.e., the magnetic field increases the forward resistance. Where very strong magnetic fields are used, the Lorentz force is so large that the resistance increases within increasing magnetic field, whichever of the two magnetic field polarizations is employed, but to different extents, i.e. the magneto resistance is always positive. The magnetic field sensitivity of the diode is not impaired.